IMPROVEMENTS RELATING TO FACE MASKS

Abstract

Face masks, including filter masks, having improved stability, including face masks having a sealing member (25) depending from the mask body for engagement with the wearer's face, the mask body comprising a nasal portion (27) for accommodating the nose of the wearer, a mouth portion (26) for accommodating the mouth of the wearer, and cheek portions (28) extending laterally across the wearer's cheeks.

Claims

1. A face mask comprising a mask body that defines a cavity for accommodating the nose and mouth of a wearer and from which a wearer inhales respiratory gases, in use, and a sealing member depending from the mask body for engagement with the wearer's face, the mask body comprising a nasal portion for accommodating the nose of the wearer, a mouth portion for accommodating the mouth of the wearer, and cheek portions extending laterally across the wearer's cheeks.

2. A face mask as claimed in claim 1, wherein the cheek portions may extend laterally across the wearer's cheeks between the upper edges of the malar bones and the lower edge of the mandible of the wearer.

3. A face mask as claimed in claim 1 or claim 2, wherein the face mask extends laterally across the wearer's cheeks such that an edge of the mask is situated, in use, within 5 cm, or within 4 cm, or within 3 cm, or within 2 cm of the wearer's ears.

4. A face mask as claimed in any of claims 1 to 3, wherein the distance between a first side edge of the mask body and an opposing side edge of the mask body, measured along the surface of the mask body, may be between 1.2 and 2 times larger than the distance between the top edge of the mask body in the nasal region and the bottom edge of the mask body in the chin region, measured along the surface of the mask body.

5. A face mask as claimed in any one of claims 1 to 3, wherein the mask substantially covers the wearer's cheeks.

6. A face mask as claimed in any preceding claim, wherein the portions of the mask body which extend across the wearer's cheeks form a shallower cavity between the mask body and the wearer's face than the portion of the mask body which extends over the wearer's nose and mouth.

7. A face mask as claimed in any one of claims 1 to 5, wherein the cheek portions each have a first edge that extends from a left- or right-side edge of the nasal portion, and is accommodated over the malar bone of the wearer, and a second edge that extends from a left- or right-side edge of the mouth portion, such that the second edge of the cheek portion is accommodated above the lower edge of the mandible of the wearer, wherein the angle between tangent lines to the first and second edges of each cheek portion decreases with increasing lateral position.

8. A face mask as claimed in claim 7, wherein the cheek portions each further comprise a side edge which extends between a distal end of the first edge and a distal end of the second edge.

9. A face mask as claimed in claim 8 where the side edge comprises a substantially linear edge.

10. A face mask as claimed in claim 8 or 9, wherein the angle between the side edge and the first edge is between 70 and 110 degrees.

11. A face mask as claimed in any of claims 7 to 10, wherein the first edge is concave in shape.

12. A face mask as claimed in any one of claims 1 to 11, wherein the face mask is a filter mask, and the mask body is defined by the support frame and the filter.

13. A face mask as claimed in claim 12, wherein the sealing member extends about the periphery of the support frame.

14. A face mask as claimed in claim 12 or claim 13, wherein the support frame and the filter extend laterally across the wearer's cheeks in the cheek portions of the mask body.

15. A filter mask comprising a support frame and a sheet of filtering material, the support frame and the sheet of filtering material defining a mask body adapted to provide a cavity in use about the mouth and nose of a wearer, the filter mask includes a sealing member depending from at least a portion of a peripheral edge of the mask body, the sealing member comprising both an inwardly and outwardly depending lip portion relative to the peripheral edge of the mask body.

16. A filter mask as claimed in claim 15, wherein the portion of the peripheral edge of the support frame about which the inwardly and outwardly depending lip portions extend may comprise a chin portion.

17. A filter mask as claimed in claim 16, wherein the outwardly depending lip formation has a contact surface that is concave in shape.

18. A filter mask as claimed in any one of claims 15 to 17, wherein the outwardly depending lip portion is shaped so as to provide a sill or shelf formation beneath the wearer's mandible.

19. A filter mask as claimed in any one of claims 15 to 18, wherein the proximal portion of the outwardly depending lip portion engages the chin of the wearer, while a distal portion curves and extends under the chin of the wearer.

20. A filter mask as claimed in any one of claims 15 to 19, wherein the outwardly depending lip formation is shaped in the form of a chin cup.

21. A filter mask as claimed in any one of claims 15 to 19, wherein the periphery of the support frame in the vicinity of the inner and outer lip portions is shaped from a central point or region of the mask by a first radius, and the inwardly depending lip portion has an inner edge of radius which is smaller than the first radius.

22. A filter mask as claimed in any one of claims 15 to 21, wherein the periphery of the support frame in the vicinity of the inner and outer lip portions is shaped from a central point or region of the mask by a first radius, and the outwardly depending lip portion has an outer edge of radius which is larger than the first radius.

23. A filter mask as claimed in any one of claims 15 to 22, wherein the nasal portion of the sealing member comprises an inwardly depending lip portion, which presents a convex surface for contact with a wearer's face.

24. A filter mask as claimed in any one of claims 15 to 23, wherein the nasal portion of the sealing member includes reinforcement formations on each side of the nose.

25. A filter mask as claimed in any one of claims 15 to 24, wherein the sealing member and, therefore, the filter mask, may also extend laterally across the wearer's cheeks.

26. A face mask comprising a sealing member depending from at least a portion of a peripheral edge of the mask body, the sealing member comprising a chin region, a nasal region, and cheek regions intermediate the chin and nasal regions, and the sealing member further comprising both an inwardly and outwardly depending lip portion relative to the peripheral edge of the mask body, wherein the inwardly depending lip portion extends about the chin and nasal regions of the sealing member, and the outwardly depending lip portion extends about the chin and cheek regions of the sealing member.

27. A face mask as claimed in claim 26, wherein the outwardly depending lip formation in the chin region has a contact surface that is concave in shape.

28. A face mask as claimed in claim 27, wherein the outwardly depending lip portion in the chin region is shaped so as to provide a sill or shelf formation beneath the wearer's mandible.

29. A face mask as claimed in claims 26 to 28, wherein the cheek regions extend laterally across the wearer's cheeks.

30. A face mask as claimed in claim 29, wherein the cheek portions may extend laterally across the wearer's cheeks between the upper edges of the malar bones and the lower edge of the mandible of the wearer.

31. A face mask as claimed in any of claims 29 to 30, wherein the distance between a first side edge of the mask body and an opposing side edge of the mask body, measured along the surface of the mask body, may be between 1.2 and 2 times larger than the distance between the top edge of the mask body in the nasal region and the bottom edge of the mask body in the chin region, measured along the surface of the mask body.

32. A face mask as claimed in any one of claims 29 to 31, wherein the cheek portions each have a first edge that extends from a left- or right-side edge of the nasal portion, and is accommodated over the malar bone of the wearer, and a second edge that extends from a left- or right-side edge of the mouth portion, such that the second edge of the cheek portion is accommodated above the lower edge of the mandible of the wearer, wherein the angle between tangent lines to the first and second edges of each cheek portion decreases with increasing lateral position.

33. A face mask as claimed in claim 32, wherein the cheek portions each further comprise a side edge which extends between a distal end of the first edge and a distal end of the second edge.

34. A face mask as claimed in claim 33 where the side edge comprises a substantially linear edge.

35. A face mask as claimed in claim 33 or 34, wherein the angle between the side edge and the first edge is between 70 and 110 degrees, or between 80 and 100 degrees, or about 90 degrees.

36. A face mask as claimed in any of claims 32 to 35, wherein the first edge is concave in shape.

37. A face mask comprising a support frame and a sealing member, the support frame defining a mask body adapted to provide a cavity in use about the mouth and nose of a wearer, and the sealing member depending from at least a portion of a peripheral edge of the mask body and comprising a nasal portion which, in use, forms a seal against or adjacent to the nose of the wearer, the nasal portion comprising at least one reinforcing member.

38. A face mask according to claim 37, wherein the at least one reinforcing member comprises one or more ribs, corrugations or scallops positioned on each side of a nasal region of the sealing member.

39. A face mask according to claim 38, wherein the at least one reinforcing member comprises one or more corrugations or scallops, wherein the side wall of the sealing member is shaped to form the one or more corrugations or scallops, and wherein the portion of the side wall which is shaped to form the one or more corrugations or scallops has a uniform thickness.

40. A face mask according to claim 37 or claim 38, wherein the at least one reinforcing member is located on an internal wall of the sealing member.

41. A face mask according to any of claims 37 to 40, which further comprises a sheet of filtering material.

42. A face mask as claimed in any of claim 1 to 14 or 26-41, or a filter mask as claimed in any of claims 15-25, which further comprises a port, wherein the port is an inlet for respiratory or inhalatory gas.

43. A face mask according to any of claim 1-14 or 26-41, or a filter mask according to any of claims 15-25, which further comprises an additive containing silver ions.

Description

[0138] Embodiments of the invention are now illustrated, by way of example only, with reference to the following drawings:

[0139] FIG. 1 is a perspective view of a support frame of a filtration mask according to the invention;

[0140] FIG. 2 is a side view of the support frame of FIG. 2;

[0141] FIG. 3 is a perspective view of a filter of a filter mask according to the invention;

[0142] FIG. 4a is a perspective view of the filter located within the support frame of the first embodiment of a filter mask according to the invention during manufacture;

[0143] FIG. 4b is the view of FIG. 4a, without the filter;

[0144] FIG. 5 is a perspective view of the support frame and filter of FIG. 4 and a core of the mould using during manufacture of the first embodiment of a filter mask according to the invention;

[0145] FIG. 6 is a side view of a filter mask according to the invention;

[0146] FIG. 7 is a perspective view of the rear of a filter mask according to the invention;

[0147] FIG. 8 is a schematic drawing showing the connection between the support frame and the filter material formed by overmoulding of the sealing member;

[0148] FIGS. 9a and 9b are perspective views of the front and rear of a further embodiment of a filter mask according to the invention;

[0149] FIGS. 10a and 10b are perspective views of the front and rear of a further embodiment of a filter mask according to the invention;

[0150] FIG. 11 is a perspective view of the rear of a filter mask of a further embodiment of the invention;

[0151] FIGS. 12a and 12b show front and rear perspective views of a filter mask according to a further embodiment of the invention;

[0152] FIGS. 13a-d show face masks according to the invention having reinforcing members on each side of the nasal region; and

[0153] FIG. 14 shows configurations of reinforcing members which may be present in a face mask according to the invention.

[0154] A support frame 10 for use in a filter mask according to the invention is shown in FIGS. 1 and 2. The support frame 10 has a generally curved shape and comprises an integrally formed rim 11, a shield 12, a pair of first attachment formations 13 and a pair of second attachment formations 14. The shield 12 is substantially the same shape as the rim 11, but is smaller, and is offset from the rim 11 by approximately 1 cm. The shield 12 is attached to the rim 11 by four connection members 16 equally spaced about the circumference of the rim, and attached to points close to the edge of the shield. A space 15 between the shield 12 and the rim 11 extends about the periphery of the shield, interrupted only by the connection members 16. A seal supporting member 31 extends downwardly from the centre of the bottom edge of the rim 11. The seal supporting member 31 is an arcuate shaped tab which depends downwardly from the rim 11 and curves towards the rear of the support frame 10. The support frame 10 is an integrally formed component, with all features manufactured in a single injection moulding step.

[0155] A pair of first attachment formations 13 outwardly extend from a first side of the rim 11 which, in use, is located near a first ear of the wearer. The first attachment formations 13 take the form of a keyhole shaped slot through which a cord or strap (not shown) may be threaded, and secured with a knot or clamping device. A pair of second attachment formations 14 extend outwardly from a second side of the rim which, in use, is located near the second ear of the wearer. The second attachment formations 14 comprise a slot (not visible) covered by a tab 17. The tab 17 has a series of teeth 18 which provide grip. The cord or strap (not shown) passes through the slot in the attachment formation 14 from the internal side of the support frame to the external side, between the tab 17 and an edge of the slot. The teeth 18 grip the cord and reduce or prevent movement of the cord in the reverse direction.

[0156] In use, the cord or strap is secured in the upper first attachment formation 13, passes through the upper second attachment formation 14 from the internal side to the external side, through the lower second attachment formation 14 from the external side to the internal side, and is finally secured in the lower first attachment formation 13. Thus, the strap passes behind the wearer's head twice, with a loop being formed between the pair of second attachment formations 14 on the external side of the support frame. When the wearer applies tension to this loop, e.g. by pulling the loop, the cord will be pulled through the apertures, past the teeth 18 on the tab 17. The release of this tension e.g. by the wearer releasing the loop of cord, will allow the teeth 18 to grip the cord, thus preventing the cord from sliding back through the slot unless a significant force is applied. In this way, one hand may be easily used to adjust the mask to fit the wearer's head.

[0157] Injection moulding is used to produce the support frame 10, the support frame 10 being an integrally formed unit produced from injection moulded polypropylene in a single step.

[0158] Where the manufacture of the filter mask is automated, the support frame 10 is ejected from the mould onto a vacuum cup on a robot arm. A pneumatic die pushes a sheet of filter material 22 from a roll of filtration material into the support frame 10, the roll of filter material comprising a continuous series of pre-stamped sheets of filter material, heat sealed about their peripheral edges. The sheet of filter material 22 is shown in FIG. 3.

[0159] The sheet of filter material is positioned on the internal side of the support frame that is, the side of the support frame 10 which will face the wearer in use. The sheet of filtering material is located on the inwardly extending shoulder, held in place about its periphery by retention tabs 19 at either side of the rim. This support frame/filter material assembly is shown in FIGS. 4a and 4b.

[0160] The support frame/filtration material assembly is transferred into a first half of the mould and mounted to a mould core 30. A second half of the mould is sealed against the first half of the mould, forming the mould cavity. In an injection moulding step, a sealing member 25 is overmoulded to the support frame/filtration material assembly, surrounding the periphery of the sheet of filter material 22 and adhering it to the support frame 10, and forming the sealing member 25, in a single overmoulding step. The filter mask 20 is removed from the mould, e.g. using a large 20 mm pin to unpeel the filter mask 20 from the core 30, and transferred for manual attachment of an elasticated cord and subsequent packaging.

[0161] The connection between the filter, sealing member and support frame is shown schematically in FIG. 8. The periphery of the filter 91 is placed against a shoulder 94 extending laterally from the rim of the support frame 93, either before or after the support frame is placed in the mould. A thermoplastic elastomer (TPE) 92 is injected into the mould to form the sealing member. The portion of TPE 92 shown in FIG. 8 represents only a proximal edge of the sealing member. The TPE 92 is forced by the mould between the peripheral edge of the filter 91 and the rim and shoulder of the support frame 93, 94. The TPE 92 surrounds and impregnates the peripheral edge of the filter 91, the peripheral, impregnated region being denoted 95, adhering it to the rim and shoulder of the support frame 93, 94.

[0162] Tool shutout, as shown in FIG. 8, prevents ingress of TPE 92 into the filter 91 beyond its periphery 95, ensuring that the filtering action of the filter 91 is not inhibited by TPE. As well as aiding adhesion of the support frame 93, 94 to the filter, impregnation of the peripheral edge 95 of the filter 91 with TPE may contribute to the seals at the edge of the filter, formed by heat sealing, preventing moisture or other contaminants from seeping into the structure of the filter.

[0163] A side view of a filtration mask 20 according to the invention is shown in FIG. 6. The support frame 21 is the same as that described in relation to FIGS. 1 and 2. A sheet of filtering material 22 is positioned behind the support frame 21, and is visible in the gap between the shield 23 and the rim 24, about the periphery of the shield 23. This permits air to easily flow past the shield 23 and through the filtering material 22, while still benefitting from the protection of the shield across the filtering material.

[0164] The sealing member 25 is overmoulded onto the support frame 21 and filter material 22, fixing their relative positions. The sealing member 25 comprises a chin engaging portion 26, a nose engaging portion 27 and cheek engaging portions 28. The cheek engaging portions 28 extend laterally across the cheeks, forming a seal against the softer skin on the cheek and improving the overall seal of the mask.

[0165] The sealing member 25 is formed of an elastomeric material. It provides a compressible region between the support frame 21 and the wearer's face, enabling the elastomeric material to conform to the contours of the wearer's face and provide a good seal against it.

[0166] The downwardly depending seal supporting member 31 abuts the seal in the chin region, reinforcing the seal in this region and enhancing the seal against the wearer's chin.

[0167] FIGS. 4a and 4b show the support frame/filter member assembly, with and without the filter material present respectively. The support frame 10 comprises a rim 11. The rim 11 has an inwardly extending shoulder 41 onto which a pre-cut sheet of filter material 22 is placed. Extending from a first side of the rim are first attachment formations 13, and second attachment formations 14 extend from the second side of the rim. The support frame 10 also comprises a shield 12. A series of vertical ribs 29 across the back of the shield 12 ensure that the spacing between the shield 12 and the filter material 22 is maintained.

[0168] A further embodiment of a filter mask according to the invention can be seen in FIGS. 9a and 9b, and is generally designated 100. The structure of the mask is substantially the same as that described in relation to the first embodiment depicted in FIGS. 6 and 7, except that the mask 100 further comprises a mushroom valve 101 (shown in the closed position). In the chin region, the rim 102 of the support frame comprises an upwardly projecting portion 103, and the shape of the shield 104 and filter material 105 corresponds to the shape of the inner periphery of the rim 102 such that they accommodate the upwardly projecting portion 103. The filter material 105 is sealed along the periphery of the rim 102 of the support frame, including the upwardly projecting portion 103, by a surrounding rim of TPE 106. The upwardly projection portion comprises an aperture, with the mushroom valve 101 being formed in the aperture as part of the overmoulding step which also forms the sealing member 107. The mushroom valve 101 permits exhaled air to escape without passing through the filter material 105. The mushroom valve 101 could alternatively be accommodated within the shield 104.

[0169] A further embodiment of a filter mask shown in FIGS. 10a and 10b, which is generally denoted 110, has substantially the same structure is described in the second embodiment in relation to FIGS. 9a and 9b, but shows an elbow connection 111 in place of the mushroom valve. The elbow connection 111 permits connection of the mask 110 to other medical equipment, such as a nebuliser.

[0170] A further embodiment of a filter mask of the invention is shown in FIG. 11. The filter mask has all of the features described in relation to FIGS. 6 and 7, but further comprises a series of corrugations 121 at each side of the nasal portion of the sealing member, to provide reinforcement to the seal. The corrugations 121 extend in a direction perpendicular to the support frame, and extend across a central portion of the seal. The corrugations 121 are integrally formed in the wall of the sealing member, such that they are visible from both the inside and the outside of the sealing member.

[0171] FIGS. 12a and 12b depict a filter mask 140 comprising a filter 141, a gas inlet 142, a mask body 143, a sealing member 144 depending from a periphery of the mask body 143, and first and second pairs of attachment members 145, 146, which are as described in relation to FIGS. 4a-b. The gas inlet 142 may be a spigot. An aperture in a first side of the mask body 143 houses the filter 141, while the gas inlet 142 is inserted through or integrally formed with a second side of the mask body 143, such that the filter 141 and gas inlet 142 are located on different sides of the wearer's nose and mouth, in use. During use, oxygen flows from the gas inlet 142 to the filter 141, washing over the wearer's mouth and nose, providing a continuous flow of oxygen and helping to draw away exhaled gases.

[0172] FIG. 13b-d show a cross-section of the mask 150 along the line X-X marked on FIG. 13a. These drawings show reinforcing members in the nasal region.

[0173] FIG. 13b shows a series of ribs 151 either side of the nasal region of the sealing member 152. The ribs 151 extend in a direction perpendicular to the mask body, and are located on an internal side wall of the sealing member 152. The ribs provide reinforcement to the sealing member 152, preventing distortion of the sealing member 152 in the nasal region.

[0174] FIGS. 13c and d show reinforcing members 153, 154 integrally formed within the wall of the sealing member 152. The reinforcing members 153, 154 take the form of corrugations or scallops in the side wall of the sealing member, each corrugation 153 or scallop 154 extending in a direction perpendicular to the mask body. The wall of the sealing member 152 in the region of the reinforcing members 153, 154 retains a uniform thickness. The reinforcing members 153, 154 support the sealing member 152 in the nasal region. Other arrangements of reinforcing members are shown in FIG. 14.